1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a storage medium.
2. Description of the Related Art
To improve the productivity and economize the count number in a print operation, an image forming apparatus capable of performing aggregate imposition is conventionally proposed to print a plurality of screen images on the same surface of a bigger sheet that is several times larger in size than a required sheet. Regarding economizing the count number in printing, the copy fee per sheet generally remains the same regardless of the paper size in many cases. For example, the print fee can be reduced if two images of A4 size can be disposed on a single sheet of A3 size. In this case, a print job includes post-processing to cut the printed sheet into several sections corresponding to respective screen images after the printing is completed. As a result, a desired print product can be obtained without increasing the count number in each print operation.
Further, regarding the productivity, the print speed in a case where the long side of an A4 sheet is positioned at the head in a sheet feeding operation is not so different from the print speed in a case where the short side of an A5 sheet is positioned at the head. Further, the sheet feeding operation of an A5 sheet with its long side positioned at the head can be controlled to be the same in speed as the sheet feeding operation of an A4 sheet with its long side positioned at the head. Accordingly, in a case where the required copy size is A5, the productivity does not substantially decrease even when two screen images are disposed on a single sheet. Rather, the productivity may be improved because the amount of sheets is doubled through a cutting process.
Japanese Patent Application Laid-Open No. 2003-305915 discusses a cutting based aggregate imposition method for realizing imposition in which divided sheets can be arranged correctly in page order when respective sheets are stacked after the cutting process is completed. In the following description, the above-described cutting based imposition method is referred to as “cut and stack imposition” method.
The cut and stack imposition is, for example, available in the field of variable data print (VDP) that enables a user to obtain a printout result differentiated for individual clients. The variable data print (VDP) is a technique capable of obtaining a printout result, which is partly different depending on each record, based on client data registered beforehand when each job is processed. The “record” is a unit of sequential VDP processing. For example, when the printing is performed differently for each client, one record is constituted by print data dedicated to each client.
A VDP job is associated with a variable object variable depending on each record. The variable object is combined and printed together with a master object that serves as a common background of the record. The VDP job, even if a plurality of records is included, can be managed as a single job. Further, an object to be used for a plurality of times in the job is referred to as “reusable object.” The reusable object can store a rasterized bitmap image or intermediate data, which can be reused in the second time or after, so that the processing speed can be increased.
When the variable data print is widely used, it is useful to employ a technique capable of processing a VDP job in a parallel fashion to further increase the processing speed of the VDP job. A relevant conventional technique is discussed in Japanese Patent Application Laid-Open No. 8-297560. The conventional parallel processing technique includes analyzing a page description language (PDL) of print data and dividing a job into respective pages (or objects) to be generated as print data. The conventional technique further includes performing parallel processing to generate a print image using a plurality of Raster Image Processors (RIP) to increase the processing speed.